Variable pitch propeller



Nov. 10,1931. s. BORCHARDT v I 1,831,284

VARIABLE PITCH PROPELLER Filed Oct. 8, 1930 3 Sheets-Sheet l Q ByAtlomey S. BORCZHARDT wmmam PITCH PRQPIS-W- Shets-Sheet 2 Filed fist.18. 193- Nov. 10, 193i.

Nov, 10, 1931. s. BORCHARDT TECH PJEQPE' LIABLE P 3 Sheets-Sheet 3 Filed06%.. 18, 1938 Inuenior Era/Zed?- Patented Nov. 10, 1931 UNITED STATESPATENT OFFIC STANLEY BORCHARDT, OF WAUWATOSA, WISCONSIN VARIABLE PITCHPROPELLER The present invention relates to a variable pitch propellerfor aeroplanes and the like and has for its prime object to provlde apropeller in which the pitch of the blade may be changed at will in aneasy and expeditious manner.

Another very important object of the invention resides in the provisionof a variable pitch propeller of this nature which is simple in itsconstruction, strong and durable, thoroughly efficient and reliable inuse and operation, compact and convenient 1n its arrangement of parts,easy to assemble and d1sassemble, and otherwise well adapted to thepurpose for which it is designed.

With the above and numerous other objects in view as will appear as thedescription proceeds, the invention resides in certain novel features ofconstruction, and in the combination and arrangement of parts as will behereinafter more fully described and claimed.

. In the drawings:

Figure 1 is a fragmentary slde elevation of an aeroplane showing apropeller structure associated therewith embodying the features of myinvention,

Figure 2 is a longitudinal section through the propeller structure, I

Figure 3 is a sectional view taken substantially on the line 33 ofFigure 2,

Figure 4 is a sectional View taken substantially on the line 44 ofFigure 2,

Figure 5 is a detail view of the slidable block,

Figure 6 is a transverse section taken substantially on the line 66 ofFigure 3,

Fi ure 7 is a transverse section taken substantially on the line 7-7 ofFigure 3,

Figure 8 is a perspective view of one of the shoes, and

Figure 9 is a detail sectional view through a portion of the hub andshowing how the disk which is connected to the propeller shank is heldin a recess in the hub.

Referring to the drawings in detail it will be seen that the numeral 5denotes a propeller shaft having an elongated squared portion 6terminating in a reduced rounded terminal 7, the extremity of which isthreaded as indicated at 8. A hub 9 is provided with a bore,

a portion of which fits snugly over the rounded terminal portion 7 andover an adjacent part of the squared portion 6.

At opposite points this hub is formed with radially ends of which aredisposed disks 11 each being between 'a pair of washers 12. Shanks 14extend outwardly from the centers of the disks 11 through the outerwasher 12 and at their outer ends merge into of nuts 16 are disposedabout each shank 14 and threaded inside the recesses 10. Cap nuts 17 arethreaded in the outer ends of the recesses about the shanks 14 and formbearing therefor. The outer surfaces of these nuts 17 have hexagonalextensions 18 so that a wrench or the like may be used thereon.

The rear portion of the hub is provided with slots 19 leading to thedisks 11 and cranks 20 are engaged withthe disks 11 and extendrearwardly through the slots 19.

An elongated block 21 has a longitudinally extending square bore toreceive the squared portion 6 and to permit the block to rotatetherewith and to be slidable thereon.

The rear end of the block 21 has an annular groove 22 with which isengaged a fork 23. A pull and push rod 24 is engaged with the fork 23and is operable from a convenient point within the aeroplane as isclearly indicated in dotted lines in Figure 1 so that the block may beslid back and forth.

The forward portion of the block21 is of a square construction and hasopposed faces formed with diagonal grooves 26 disposed obliquely withrespect to each other. These grooves 26 are mortised as isindicated inFigure 6 and slidably receive shoes 27' having ribs 28 extending intothe mortises of the groove. Studs 29 the shoes to receiye the rear endsof the cranks. Now when the block'is moved longitudinally of theshaft itwill be readily appreciated that the shoes will be moved laterally withrespect to the axis of the shaft thereby oppositely swinging the cra'nksand varying the pitches of the propellers 15.

A sectional housing 30 is formed with an inturned flange 31 at one endfitting in an annular groove 32 on the rear portion of the disposedrecesses 10 inthe inner 55 propellers 15. A. pair 60 project outwardlyfrom 90 hub 9 and at the rear end of the housing is an inturned flange33 terminating circum acent the slidable block 21 to the rear of itssquared forward end portion. A nut 34;- on the threaded terminal 8 holdsthe hub in place on the shaft and any suitable locking means such as acotter pin or the like may be used in connection therewith.

It is thought that the construction, utility, operation and advantagesof this invention will now be quite apparent to those skilled in thisart without a more detailed description thereof.

The present embodiment of the invention has been described inconsiderable detail merely for the purposes of exemplification since inactual practice it attains the features of advantage enumerated asdesirable in the statement of the invention and the above description.

It will be apparent that changes in the details of construction, and inthe combination and arrangement of parts may be resorted towithout-departing from the spirit or scope of the invention ashereinafter claimed or sacrificing any of its advantages.

Having thus described my invention, what I claim as new is:

In a variable pitch propeller construction, a hub having oppositelydisposed recesses therein, disks in the inner ends of the recesses,shanks projecting outwardly from the disks and merging into propellers,means for rotatably holding the disks in the recesses, cranks extendingradially from the disks, a shaft on which said hub is mounted, saidshaft having a squared portion, a block slidable on the squared portionand having oppositely disposed fiat surfaces formed with diagonalgrooves, shoes slidable in the grooves and connected with the cranks,and means for sliding the block.

In testimony whereof I affix my signature.

STANLEY BORCHARDT.

